Field of the Invention
The present invention relates to a field effect transistor.
Discussion of the Background
Japanese Unexamined Patent Application Publication Nos. H04-280438, 2006-253559, and 2007-165446 disclose known field effect transistors. Such field effect transistors include a semiconductor layer including a channel, and a source electrode, a drain electrode, and a gate electrode disposed on the semiconductor layer. Japanese Unexamined Patent Application Publication Nos. H04-280438, 2006-253559, and 2007-165446 propose a structure that an insulating region or a recess portion is formed in the semiconductor layer for a variety of purposes. In Japanese Unexamined Patent Application Publication No. H04-280438, the insulating region is formed in the semiconductor layer for realizing a fine-structured channel. In Japanese Unexamined Patent Application Publication Nos. 2006-253559 and 2007-165446, the recess portion is formed in the semiconductor layer for increasing a contact area with the electrodes.